Case law in the USA

The US Supreme Court made rulings in the 80s and 90s that were interpreted as allowing software patents, however, none of these rulings dealt with the question explicitly. A 2007 ruling in KSR v Teleflex indicated that the scope of patenting was to be narrowed. A 2008 ruling of the Federal Circuit court in re Bilski introduced the machine-or-translation test which narrows or closes the scope for patenting software ideas.

The Supreme Court have decided to review the Bilski ruling in late-2009/early-2010 and are accepting amicus briefs.